Make the glaze:
In a small saucepan over medium heat, combine the miso paste, brown sugar, mirin, soy sauce, sesame oil, ginger, and garlic. Stir constantly for 2–3 minutes until the glaze is smooth and slightly thickened. Do not boil. Set aside.
Marinate the salmon:
Pat salmon dry. Place in a shallow dish or zip-top bag. Pour about two-thirds of the glaze over the fillets. Cover and refrigerate for 30 minutes to 4 hours.
Sear the salmon:
Preheat oven to 400°F (200°C). Heat olive oil in an oven-safe skillet over medium-high heat. Add salmon, skin-side down, and sear for 2–3 minutes until golden.
Bake to finish:
Flip the salmon, brush with a bit more glaze, and transfer the skillet to the oven. Bake for 6–8 minutes, or until salmon flakes easily and reaches an internal temp of 125°F.
Serve:
Plate over jasmine rice and steamed snow peas. Drizzle with remaining glaze and garnish with sesame seeds or scallions if desired.